Brake system for railway vehicles

ABSTRACT

The invention relates to a brake system for a railway vehicle. Said brake system comprises a main air reservoir line which is fed by an air compressor unit. Every bogie truck is provided with at least one compressed-air line which is connected to the main air reservoir line either directly or via a stop valve, a non-return valve and a compressed-air reservoir. The compressed-air line feeds, for example, the service brake valves for impinging the brakes of the bogie truck or a control unit for the spring-loaded brake and/or other control units for other auxiliary components. The service brake valves and/or the spring-loaded brake and/or other auxiliary components are controlled via at least one local, electronic brake control unit.

CROSS-REFERENCE

This application is a continuation of U.S. application Ser. No.09/830,179 filed on Aug. 2, 2001, now U.S. Pat. No. 6,669,308, which isa 371 of Application No. PCT/EP99/08015, filed Oct. 22, 1999.

BACKGROUND AND SUMMARY OF THE INVENTION

The present invention relates to a pneumatic brake system for a railwayvehicle as well as to a bogie and as well as to a brake control unit.

Modern brake systems for railway vehicles comprise components which areto be controlled pneumatically and/or hydraulically as well aselectronically. In the standard-gauge railway domain, pneumatic systemsare usually used, by means of which the braking devices of the railwayvehicle as well as additional auxiliary units, such as the spring-loadedbrakes, the wheel flange lubrication system, the cleaning block, thesanding device, etc., are controlled. For this purpose, the railwayvehicle has a compressed-air generating device which, as a rule,directly feeds a main air reservoir line as well as, by way of a trainbrake valve, a main air line. The braking device of the train vehicleand the auxiliary units are in this case supplied with compressed air bythe main air reservoir line. For this purpose, auxiliary units of thetrain formation, such as door opening devices, are also controlled bythe main air reservoir line. The main air line supplied by way of thetrain brake valve is used for controlling the individual car brakes of atrain formation and can also be utilized as an additional control forthe brake systems of the train vehicle.

However, such a construction requires extensive pneumatic installationsin the train formation and particularly between the engineer's cab andthe bogies of the train vehicle. As a result, the freedom ofconstruction is limited when such railway vehicles are further developedbecause considerable space is required. Other disadvantages are theweight of these installations and the expenditures required particularlyfor the mounting. Such a pneumatic control unit is known, for example,from European Patent Document EP 0 855 319 A2.

From German Patent Documents DE-AS 21 05 564 and DE 28 01 778 A1 by thesame applicant, for example, electro-pneumatic brakes for railwayvehicles are known. In U.S. Patent Documents U.S. Pat. No. 5,503,469 andU.S. Pat. No. 5,538,331, electro-pneumatic brake systems are alsodescribed in which central computers are used as the control unit inorder to simplify the system and save components, such as microswitches.In addition, the central computer permits a linking of differentelectro-pneumatic vehicle systems by means of a correspondingprogramming. From German Patent Document DE 28 40 262 C2, it is finallyknown to process current operating data in a central computer and takedata into account when controlling the braking devices.

German Patent Document DE 38 33 922 A1 as well as European PatentDocument EP 0 363 827 A2 by the same applicant disclose a brake systemfor railborne bogie vehicles which has a hydraulic pressure supply unitin each of the bogies.

From German Patent Document DE 40 22 671 A1, an electronic brake systemfor road vehicles is known whose electronic system has a decentralizedconstruction, with a central module and several wheel modules.Furthermore, in German Patent Document DE 43 39 570 A1, an electronicbrake system for motor vehicles or road vehicles is described which hasa central module and brake modules assigned to the brake circuits orwheel groups or wheels, which brake modules receive defined desiredbrake pressure values from the central module. The brake pedal isconnected with a master brake cylinder. The central module is to carryout antilock system/wheel slip control system computations and isresponsible for the brake power distribution to the wheels of the roadvehicle. Further, German Patent Document DE 196 34 567 A1 describes anelectronic brake system for motor vehicles.

German Patent Document DE 26 11 924 C2 describes a bolster bogie forfast-travelling railway vehicles in the case of which the axles aresupported by way of the axle bearing housing by means of a primarysuspension on the approximately H-shaped bogie frame and are pivotallyconnected to the latter by means of spring leaf control arms. By way ofpneumatic springs, the bolster rests on spring troughs. The pneumaticsprings are acted upon by compressed air from auxiliary air reservoirsarranged in the bolster. Furthermore, International Patent Document WO93/01076 describes a bogie for railway vehicles capable of travelling athigh speed having an auxiliary air reservoir fastened on the bolstersupport.

In addition, German Patent Document DE 43 22 716 A1 discloses a framefor commercial vehicles which is constructed of a front-axle partialframe, a center partial frame and a rear-axle partial frame. Thefront-axle partial frame and the rear-axle partial frame consist of sidemember segments connected with cross members. The central second partialframe takes over the function of the actual side members and connectsthe first partial frame with the third partial frame. In this case,closed structural parts of the side member segments of the centralpartial frame may be constructed as operating medium storage devices.Furthermore, German Patent Document DE 39 40 250 A1 discloses pressuremedium reservoirs arranged in a motor vehicle or in a passenger car insupport member profiles.

A device for detecting and monitoring the braking effect of a railbornetraction vehicle in the event of an emergency braking is suggested inGerman Patent Document DE 195 10 755 A1. In order to achieve, in thecase of a braking device for a train formation, which consists ofseveral train units with at least one traction vehicle and severalpertaining train vehicles respective, a delay-free braking operation andavoid an unnecessary operation of the control valves in the trainformation, it is suggested in German Patent Document DE 197 39 444 A1that, for the synchronous admission of pressure medium to the pressureline by the control valves, the train bus is in a bidirectionalcommunication with a command apparatus, the train bus controlling thebrake valves in the train formation for the synchronous operation of thebrakes.

For simplifying the system, German Patent Application DE 195 13 004 A1suggests a combination of the electronic and pneumatic or hydrauliccontrol and/or monitoring elements of the brake system in a unit in theengineer's cab. This construction method has the advantage that theinstallation expenditures are reduced at least in the vehicleconstruction. However, also in this type of construction, an extensivepipework is required between the engineer's cab and the bogies of therailway vehicle in order to permit the pneumatic controlling of thebrake units and auxiliary units.

Furthermore, such brake systems for a railway vehicle must haveemergency braking devices by means of which the railway vehicle canreliably be stopped in the event of a disturbance. For this purpose,conventional brake systems have pneumatic devices which, for example,when an emergency brake is operated, start the operation of the brakesof the vehicle. This takes place, for example, by means of purelypneumatic operating lines or by electric signal lines which controlemergency brake valves which operate according to the quiescent-currentprinciple.

This system, which has been successful in practice, however, has thedisadvantage that considerable expenditures are required for itsimplementation. Vehicles, which are equipped with an electric emergencybrake signal line, must be equipped with purely mechanical-pneumaticelements for adapting the braking power to the situations, for example,the loading condition. In addition to high-expenditure pneumaticcomponents, an extensive laying of pipes is also required for thispurpose.

In addition, a considerable number of corresponding devices acting uponthe pneumatic system are required so that also a passenger can initiatean emergency braking signal. Even when a disturbance occurs at adifferent point in the pneumatic system, an emergency braking has to beautomatically initiated.

The known emergency system therefore requires extensive installationexpenditures. This has a disadvantageous effect on the costs formaterial and mounting. It is another disadvantage that this system isrelatively heavy, which has a disadvantageous effect on the energyconsumption during the operation of the railway vehicle.

It is therefore an object of the invention to provide a brake system fora railway vehicle in which the control system is simplified.

In a particularly advantageous manner, the installation expendituresbetween the engineer's cab and a bogie can be reduced according to theinvention. In this case, by means of the at least one compressed-airline, auxiliary units can also be operated, in addition to the servicebrake. As a result, the system is significantly simplified and thematerial and mounting expenditures are lower than in the case of knownmethods of construction. In addition, the weight of the entirearrangement can also be reduced.

In a particularly advantageous manner, a decentralizing of theelectronic brake control unit by means of local electronic brake controlunits in the bogies permits also a displacement of the necessarypneumatic devices into the bogies, whereby the expenditures for thepipework are significantly reduced. The object of the pneumatic systemis therefore limited according to the invention to the initiation of thedesired function at the site, that is, in the bogie, while thecontrolling of these functions can take place by way of the electronicsystem. Significantly lower expenditures are necessary for theelectrical wiring required for this purpose than for the pneumaticcontrolling according to the prior art. In particular, the spacerequirement for the control devices and the weight can be reducedsignificantly. Furthermore, the mounting expenditures are considerablyreduced. The constructive expenditures for the overall system is furtherreduced in this manner, in which case a modular construction of thedecentralized control devices can be achieved with a prior mounting inthe bogies.

It is another advantage that the reliability of the system is alsoincreased in this manner. If, in the case of the brake system accordingto the invention, a single local brake control unit of several controlunits fails, this does not yet decisively impair the operability of theoverall brake system of a train formation.

As a result of the fact that the local brake control unit has availableon its input side signals of the presetting device operable by theengineer and signals of local devices for detecting actual operatingvalues—such as slip, axle load, rotational wheel speed, actualdeceleration and bogies load—and/or signals of devices for themonitoring and automatic operational management (ATO, ATC, ATP), thesecan advantageously be taken into account during the respective brakingoperation. The braking performance of the railway vehicle and of thetrain formation can therefore be controlled in a still more exactmanner.

In particular, as a result, actual operating data can be exchangedbetween the individual decentralized modules, whereby the stability ofthe train formation in the event of a braking is further increased. Thebraking performance of the railway vehicle can therefore be maintainedin a comparable manner also in the case of the most different railwayvehicles and environmental conditions, which significantly increases thecomfort, for example, in passenger trains.

When, by way of a central railway vehicle data bus, the brake signalsare led to at least one gateway constructed as the suitable interface,from where these and corresponding brake signals are transmitted by wayof a central braking data bus to the local brake control units, railwayvehicles of different constructions with a different vehicle processcontrol technique can also be combined with one another and together canuse the brake system according to the invention. The gateway constructedas the interface permits an adaptation of the data format to therespective railway vehicle type and its control logic.

When, in contrast, only railway vehicles with a process controltechnique of the same construction are connected with one another, thebrake signals can advantageously alternatively be transmitted directlyfrom the central railway vehicle data bus to the local brake controlunits. As a result, the constructional expenditures for the brake systemare reduced further.

It is also advantageous for the local brake control unit to be placed,with respect to the axle and/or the bogie, within the bogies or on thecar body in the area of the bogie. This module can then be assembledbeforehand, which simplifies the assembly of the overall system. It isfurther achieved in this manner that the local brake control unit isarranged in the proximity of the area in which it is to carry out itseffect. This reduces the expenditures for the control logistics and, inparticular, only short line routes are required.

When the local device for detecting current operating values is arrangedwith respect to the wheel and/or with respect to the axle and/or in thebogie, here also, these data can be detected at the site and can betransmitted along a short route into the local brake control unit. Longconnection lines with the resulting danger of damage to these lines cantherefore be avoided and the data can be utilized directly.

It is also advantageous for the respective local brake control unit tohave data available by means of which a linking of signals of presettingdevices can take place with signals of the operating-value detectiondevice. This information can then be effectively used for optimizing thebraking operation.

When, by means of the data available to the local brake control unit, aconversion of the brake signals takes place such that a wear of thebrakes can be achieved which is as uniform as possible, the maintenanceintervals for the railway vehicle can be extended. As a result of theuniform wear of the brakes, these are then also utilized in a moreoptimal manner, because the brakes on a single railway vehicle must arealways exchanged jointly even if some of the brake linings are not yetworn down. This causes advantageous savings.

As a result of the fact that the local brake control units, the traincontrol unit, the presetting devices in the control stations, the bogiesand optionally the local operating value detection devices are linkedwith one another by way of a safety loop, a still more reliableemergency braking system can also be provided. This further increasesthe safety of the brake system.

When the local brake control unit has a local electronic control system,a “fail-safe” device and a pressure control, a controlled braking can becarried out also in the event of an emergency braking, which controlledbraking takes into account, for example, vehicle parameters and actualoperating values as well as an antiskid control. This system cantherefore reliably carry out, for example, an emergency braking in whichthe length of the brake path is frequently not particularly important.

It is another advantage for the pressure control to preferably have twoseries-connected, electro-pneumatic valves for regulating the brakepressure by ventilating or bleeding corresponding to the present desiredbrake signal value and the present antiskid information. As a result ofthe two series-connected valves, desired pressure conditions or reactiontimes can be better adjusted.

When the two valves are constructed as solenoid valves with a preferablylow performance, the switching consumption can be minimized, while fastreaction times can nevertheless be achieved.

As a result of the fact that the pressure control has a flow intensifierarranged downstream of the two valves, a sufficient pneumatic pressureor a sufficient fluid flow rate can be provided at the brake cylinders.As a result, better switch characteristics can be achieved in the brakesystem according to the invention.

In addition, according to the invention, a reliable emergency brakingsystem can be implemented at lower constructive expenditures when anemergency braking is triggered by means of an electric signal, thetriggering of the emergency braking being monitored by a fail-safedevice which activates a fall-back level when the emergency braking isnot correctly implemented. Thus, the emergency braking system of theknown constructions, which is characterized essentially by pneumaticcomponents, is replaced by a system in which the controlling of theemergency braking system utilizes the capabilities of the electroniccontrol system of the railway vehicle for initiating and implementing anemergency braking. The electric emergency braking system is utilized fortriggering the emergency braking and in the process is monitored by afail-safe device. As a result, it is ensured that, in the event of anincorrectly operating electronic control system, an emergency braking isnevertheless initiated because, by means of the fail-safe device, afall-back level can be activated.

The present invention results in a particularly reliable safety system.Furthermore, the installation expenditures and the space requirement forthe electrical line are significantly lower than those for the pneumaticline in conventional systems. Also, the weight of the entire safetydevice can be significantly reduced. The brake system according to theinvention can therefore produced more rapidly and at lower cost.

As a result of the fact that, during the operation without emergencybraking, the above-mentioned electric signal is transmitted in the formof a normal operating signal by way of an electric safety line, aconstantly available and reliable disturbance monitoring system can beproduced in a simple manner. In contrast to the pneumatic system inwhich a certain operating pressure is constantly applied which ismaintained by means of high-expenditure devices, the electric signal canbe provided in a simple manner by means of known devices.

It is another advantage for the emergency braking to be triggered in theevent of an emergency braking by a corresponding emergency brakingsignal or the cessation of a normal operating signal. This creates thepossibility of triggering such an emergency braking passively as well asactively. The reason is that if the line for the electric signal in thetrain formation is interrupted, for example, by the tearing-off of avehicle or the like, this will automatically lead to an emergencybraking without any additional intervention by a person. However, inaddition, the train engineer or a passenger can also, by way of anemergency braking device, initiate a corresponding emergency brakingsignal, or cause the interruption of the electric signal. In this case,the interruption of the normal operating signal is the constructionallysimpler variant.

By using the electronic control system also for emergency braking, incontrast to conventional brake systems, the same actuators(electro-pneumatic valves) can also be used for adjusting the emergencybrake pressure. This further reduces the constructional expenditures.The desired pressures can be adjusted very well in this manner.

As a result of the fact that, in the normal operation, the controllingof the service brake valves as well as the activating of the controlunit for the spring-loaded brake and/or of the additional control unitsfor the additional auxiliary units takes place by local electronic brakecontrol units, which are connected with one another by way of a commonbraking data bus, the braking performance at the individual axles can bemutually coordinated. The braking operation can therefore be controlledeven better. This permits particularly a taking-into-account ofvehicle-specific values, such as the type, length and weight of thetrain formation.

This is particularly useful in the case of engineer-caused emergencybraking or safety braking in order to ensure a stopping under definedconditions in the event of a failure of the braking-related devices. Forthis type of braking, a certain safety must be ensured without alwaysrequiring a stopping distance which is as short as possible. This typeof emergency braking therefore ensures that the vehicle is caused tostop, in which case a stressing of a passenger because of occurringdecelerations on the railway vehicle can be controlled within certainranges.

When the brake system has a main air line, which is fed by way of atrain brake valve by the compressed-air generating device, whichoperates the brake by way of a control valve, the invention can also beused in railway vehicles constructed in this manner.

As a result of the fact that, when the fall-back level is activated, apreset brake pressure is fed to the brakes, it is ensured that asufficient brake pressure can be provided when an emergency braking isrequired.

If the preset brake pressure is a fixedly set brake pressure whichremains unchanged during the operation, the constructional expendituresfor the brake system can be further reduced because control elements canbe eliminated.

When the brake pressure is adapted to the load of the vehicle, thebraking operation can be carried out in a still more targeted and morecontrolled manner.

Furthermore, the invention can provide a brake system for a railwayvehicle in which the constructional expenditures for the control systemof the service brake and possible auxiliary units are reduced becausethe check valve and/or the compressed air reservoir can be arranged inthe bogie. As a result of this constructional decentralizing of thebrake system, the devices required for the function can advantageouslybe arranged where they are to have their effect. Since, as a result,only one feed line from the main air reservoir line is required betweeneach bogie and the vehicle body, the constructional expenditures betweenthese areas are significantly reduced.

Another advantage is the fact that, in this manner, very short pipepaths occur in the bogie, for example, for the distribution of thecontrol pressure to the individual axles. As a result, the costs for thematerial as well as the weight of the arrangement can be reduced.

It is also an advantage that the check valve and/or the compressed-airreservoir can be mounted beforehand in the bogie and the final assemblyof the railway vehicle is therefore significantly simplified. As aresult, more favorable manufacturing sequences can be achieved, whichhas advantageous effect on the manufacturing duration and the costs.

The brake system according to the invention also permits a significantlogistic simplification with respect to known systems, whereby it can bemonitored in a more reliable and simpler manner.

Another advantage is the fact that more space for other devices isavailable in the vehicle body. In this case, the arrangement of thecheck valve and/or of the compressed-air reservoir in the bogie isrelatively unproblematic because sufficient space exists here.Furthermore, the constructive possibilities for the design of therailway vehicle are expanded.

As a result of the fact that the frame or other constructive elements ofthe bogie are constructed at least in sections as compressed-airreservoirs, the space requirement in this area can be further reduced.In this case, the frame structure of the bogie usually produced as awelded construction is utilized in a particularly favorable manner.Thus, hollow spaces existing in the frame of the bogie, in addition totheir static utilization, will have an additional use. This reduces theconstructive expenditures because no additional compressed-air reservoirhas to be arranged in this area. The tightness in the frame required forreceiving the compressed air can be produced by conventional means byseal welding, etc.

As an alternative, the frame or other constructive elements of the bogiecan also be used, at least in sections, for receiving the compressed-airreservoir. The clearances existing in the frame structure will then beadvantageously utilized so that the space requirement for thecompressed-air reservoir can be minimized. In this case, it is alsopossible to construct the frame structure as a partially or completelyclosed covering in one area and to insert the compressed-air reservoir.The frame can then also be used as a protective element for thecompressed-air reservoir against outside influences.

When at least one other control unit is used as a monitoring unit formonitoring the triggering of an emergency braking, the advantage of anincreased protection against failure is obtained. The emergency brakingsafety line is connected with the control unit and the fail-safe device.As a first control step, the latter monitors an output signal of thecontrol unit in order to ensure that the control unit has correctlyinitiated the controlled emergency braking. Should this not be so, aswitching to the pneumatic fall-back level is caused; that is, apneumatic emergency braking of the system is caused. The use of anothercontrol unit as an additional monitoring unit or second control stephelps to ensure that a switching to the pneumatic fall-back level reallyonly has to take place in an absolute emergency. It also permits animproved checking and load-dependent controlling of a correctlyinitiated controlled emergency braking, so that vehicle specific dataand actual operating values can be taken into account during theimplementation of the emergency braking on the basis of the comparativevalues of the additional monitoring unit or second control step in amore differentiated manner. This results, for example, in an improvedslip control and thus in an optimal utilization of the coefficient ofadhesion for achieving a required stopping distance and also helps toavoid wheel flats as well as resulting repair costs. Even in the eventof a failure of the first monitoring unit, a reliable emergency brakingwill be ensured in this manner. The additional monitoring unit or secondcontrol step can preferably be housed in another, second bogie.

According to another aspect of the present invention, a bogie for arailway vehicle is provided in which the frame is constructed at leastin sections as a compressed-air reservoir. This bogie according to theinvention is characterized by a functional multiple utilization. Thus itis normally used also for the bearing of the axles and for receiving theload applied by the car body. In addition, it is used as a hollow bodyin which compressed air can be stored. The bogie according to theinvention therefore represents a particularly advantageous module forsimplifying a railway vehicle. As a result, important constructive,assembly-related and financial advantages can be achieved.

As an alternative, according to another aspect of the invention, a bogieis provided for a railway vehicle, in the case of which the frame and/orother constructive elements of the bogie are constructed at least insections for receiving a separate compressed-air reservoir. As a result,it is possible to receive in the interior of the bogie a compressed-airreservoir, which is therefore arranged in a protected manner, withoutthe requirement of significant additional space.

When a check valve of a compressed-air line is arranged in or on thebogie, which check valve is provided for feeding compressed air from themain air reservoir line to service brake valves for acting upon brakesof the bogie or for feeding the control unit for the spring-loaded brakeand/or additional control units for other auxiliary units, a bogiemodule can be provided which already integrally has important devicesrequired for controlling a brake system. Thus, such a bogie canadvantageously contribute significantly to reducing the mountingexpenditures for a railway vehicle.

According to another aspect of the present invention, a brake controlunit is provided for a brake system of a railway vehicle, which ischaracterized in that the brake control unit is arranged in the bogie,braking signals being supplied by way of a central braking data bus tothe brake control unit, and the brake control unit being provided forcontrolling service brake valves and/or for controlling thespring-loaded brake and/or for controlling additional auxiliary units.

The brake control unit according to the invention can thus be used as amodule, which is independent per se, on the bogie and permits freedomwith respect to the vehicle construction. Furthermore, theabove-discussed additional advantages can be achieved by means of thisbrake control unit.

Other objects, advantages and novel features of the present inventionwill become apparent from the following detailed description of theinvention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of the construction of the brake systemaccording to the invention;

FIG. 2 is a schematic overview of detailed devices of the brake systemaccording to the invention on a bogie;

FIG. 3 is a detailed view of the electro-pneumatic pressure controldevice of the brake system;

FIG. 4 is a schematic representation of the pneumatic brake module;

FIG. 5 is a schematic representation of the signal paths for a brakesystem according to the invention; and

FIG. 6 is another representation of the brake system according to theinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to the schematic representation in FIG. 1, a railway vehicle 1essentially has a vehicle body 2 and, in the present embodiment, hasthree bogies 3. The railway vehicle 1 is illustrated here as a tractionvehicle, in which case additional driven or non-driven vehicles can becoupled for forming a train formation.

FIG. 1 illustrates the electronic controlling of the brake system of therailway vehicle 1. A central control unit 21 and a compressed-airgenerating device 22 are arranged in the vehicle body 2. By means of avehicle data bus 23, the central control unit 21 receives operating dataconcerning the entire railway vehicle or the entire train formation. Thecontrol data for the brake system of the railway vehicle derivedtherefrom are transmitted by way of a braking data bus 24 to the airgenerating device and the local control units 31 and optionally alsoexisting function modules in the bogies 3. By way of connection units25, these data can also be transmitted to additional vehicles of a trainformation. The pneumatic devices are shown in FIG. 2.

FIG. 2 is a detailed view of an embodiment of the brake system 100. Inthis case, the brake system 100 extends on the whole over three levelsof the railway vehicle 1, which in FIG. 2 on the right-hand side, aremarked by Roman numerals I, II and III. In the area marked I, thedevices are shown which are arranged in the vehicle body 2. II shows thedevices arranged in the car body 2, while III indicates the electric andpneumatic modules arranged in a bogie 3.

Addition to the electric lines, FIG. 2 also shows pneumatic lines. Thus,a pneumatic brake module 160 is fed by a compressed-air line 111 and, inthis embodiment, by a pneumatic control line 112. The pneumatic controlline 112 and the compressed-air line 111 act upon a control valve 113with a load-dependent pressure limitation and a shut-off device, whichis arranged in the car body. In addition, the pneumatic pressure in thecompressed-air line 111 is applied to a buffer device 114 for the supplypressure with a shut-off device which is also arranged in the car body.

The output pressures of the control valve 113 and of the buffer device114 are fed to a pressure control 161 in the bogie. By way of anelectro-pneumatic pressure control device 162, a switch-over module 163and a relay valve 164 acting as a flow intensifier, this pressurecontrol system 161 sets the desired brake cylinder pressure at an outputpoint C. This output pressure is monitored by a pressure sensor 165.

The pressure control 161 also acts upon a control unit 166 for a parkingbrake P.

The local brake control unit 150 arranged in the bogie has an electroniccontrol unit 151 and a fail-safe monitoring unit 152.

As illustrated in FIG. 2, the control unit 151 is supplied by way of thebraking data bus 24 with control signals from the central brake controlunit 21. Furthermore, a loop 171 connects an emergency braking safetyline 170 with the control unit 151 and the fail-safe monitoring unit152. The control unit 151 controls the electro-pneumatic pressurecontrol device 162. When the loop 171 indicates that an emergencybraking is required, the fail-safe monitoring unit 152 will also monitoran output signal of the control unit 151 in order to ensure that thecontrol unit 151 has correctly initiated the emergency braking.

If this is not so, the fail-safe monitoring unit 152 will act directlyonto the switch-over module 163 and cause a switching to the pneumaticfall-back level, that is, the pneumatic emergency braking of the system.

When the control unit 151 has initiated a correct emergency braking,this emergency braking is carried out in a controlled manner; that is,vehicle specific data and/current operating values can be taken intoaccount during the implementation of the emergency braking, such as aslip control.

As also illustrated in FIG. 2, the central brake control unit 21 canalso be connected with the emergency braking safety line 170 in order toact by way of the braking data bus 24 onto the decentralized controlunit 151. In the case of a corresponding further development of theelectronic control unit 151 for processing such additional data, it is,however, also possible that this control unit 151 carries out theemergency braking independently and decentralized from the central brakecontrol unit 21.

FIG. 2 shows the system construction on a driving axle or a bogie of therailway vehicle 1. The constructional elements arranged in the car body2 and particularly the devices provided in the bogie 3 are provided oneach individual car body or bogie, the vehicle-body-side central brakecontrol unit 21 requiring only one per vehicle or train formation.

In the following, the function and structure of the decentralized brakecontrol module will be explained in detail. It carries out the followingfunctions on a bogie:

-   -   Controlled setting of a required brake cylinder pressure for the        bogie or for each individual axle;    -   antiskid control: Detection and analysis of the rotational axle        and wheel speeds. When unacceptably high slip values occur        during the braking, a rapid change of the brake cylinder        pressure set with respect to the bogie or axle is determined and        the brake cylinder pressure is corrected correspondingly        rapidly;    -   determination of the loading condition of the bogie, for        example, from the two bellows-seal pressures; and    -   monitoring and diagnosis of all influenced electro-pneumatic and        sensing components.

The decentralized brake control module according to this embodiment isconceived for the controlling of active brake cylinders. As explainedabove, the module described as an example is composed of a compact valvecomponent unit 160, an electronic control system 150 adapted to thecontrol function as well as monitoring component unit required forensuring the signal-related reliability of the module. In addition tothe mechanical components, this module may also include standardizedfunctional software. The brake control module receives a braking demandpreferably by way of two signal paths: The brake system bus 24 and theemergency braking loop 171.

In this case, each braking demand is processed electro-pneumatically bymeans of the electronic control system 150 and corresponding solenoidvalves as actuators. Thus, also the signal of the emergency braking loopis read in and processed by the electronic control unit. A brakingtriggered by way of this signal path is load-corrected and supported bythe antiskid control.

In the event of a serious malfunctioning of theelectronic/electro-pneumatic control, the brake control module also hasthe purely pneumatically implemented fall-back level which, in the eventof a braking demand by way of the emergency braking loop sets a fixedbrake pressure which is not load-corrected and has no antiskid control.

FIG. 3 shows a portion of the electro-pneumatic pressure control device162 and particularly the two series-connected electro-pneumatic valves180 and 181. In this case, valve 180 is used for the pressure buildup,while the other valve 181 permits the pressure reduction. As a result,while the air flow rate is low, fast reaction times can be achieved. Theflow rate intensifier 164 on the output side finally provides asufficient amount of compressed-air flow, so that the brake cylinder canbe acted upon by the desired brake pressure.

FIG. 4 shows an example of a structure of the pneumatic control suitablefor implementing the defined functions.

A pneumatic control 200 arranged in the bogie first has an auxiliarydischarge valve 201 on the side of the external feeding. By way of apressure sensor 202, the pneumatic pressure is guided to the pressurecontrol valve 203 and parallel thereto to the pressure reduction valve204. A control connection port 205 is connected in front of theadjoining emergency braking switch-over valve 206.

On the output side of the emergency braking switch-over valve 206, arelay valve 207 is connected, to which, in addition, the input airpressure is directly applied. At the output of the relay valve 207,another pressure sensor 208 is provided for detecting the brakingpressure. A check valve 209 is, in addition, connected parallel to thisarrangement. After the relay valve 207, a pressure switch 210 and acontrol connection port 211 are also provided by means of which thebrake can be released. The pneumatic pressure emitted by the relay valve207 acts upon the brake cylinder. Also, additional T-pressure sensors212 and 213 are provided.

These components will be described in detail in the following:

The pressure sensor 202 measures the supply pressure occurring at themodule 200. The two sensors 212 and 213 are used for the individualdetection of the load pressures of the two air bellows springs in orderto obtain information about the load condition of the railway vehicle.As an actuator of the pressure control circuit, the pressure controlvalve 203 contains two switching valves, as illustrated in FIG. 3. Inthe not triggered condition of the two valves, a pressure occurs whichis equal to 0 bar. In this case, two 2/2-way valves can be used, inwhich case the first valve can be constructed as an NC (ventilator) 203Aand the second valve 203B can be constructed has an NO (bleeder). As analternative, the second valve 203D can also be a 3/2-way valve. Thesepressure control valves are controlled by the electronic system and aresupplied with a stabilized voltage. In the present embodiment, thisvoltage amounts to nominally 24 volt.

The pressure reduction valve 204, which is connected parallel to thepressure control valve 203, is used for adjusting a pressure which isset as the brake cylinder pressure when the pneumatic fall-back level isactivated. The emergency braking switch-over valve 206 activates thepneumatic fall-back plane in the event of a disturbance of theelectronically-assisted braking function.

The relay valve 207 on the output side is used for intensifying the airflow rate. In this case, it meets the ventilating and bleeding gradientsrequired for the antiskid function.

The pressure sensor 208 after the relay valve 207 is used for detectingthe actual value of the braking pressure which represents a controlquantity of the pressure control circuit. In this case, the sensor meetsthe precision sufficient for the pressure controlling and its inputs aredesigned for the electronic control system of the module.

In the case of an axle-type control, these elements exist essentiallytwice.

FIG. 5 is a schematic overview of the emergency braking device in thetrain formation. In this case, the brake system 100 has the centralelectronic brake control unit 21 which is supplied by way of a data bus23 of the railway vehicle or the train formation with thevehicle-specific information and current operating data. From thecentral brake control unit 21, the braking data bus 24 leads to theplurality of local brake control units 150 which are each arranged in abogie 3. Each local brake control unit 150 is coupled to a pneumaticbrake module 160 which is supplied with compressed air by the pneumaticsystem of the railway vehicle 1. Each pneumatic brake module 160 hasbraking devices and devices interacting therewith and is controlled bythe respective local brake control unit 150.

In addition, the brake system 100 has the electric emergency brakingsafety line 170 which is connected by way of loops 171 with the localbrake control units 150. The emergency braking safety line 170 extendsthrough the train formation and, during the operation, is acted upon byan electric signal. If this signal is interrupted, this triggers in thelocal brake control units 150 the implementation of an emergency brakingin the train formation.

The pressure control in the system is implemented by the pressurecontrol circuit, the braking demand (desired braking value by way of thebraking data bus, hard-wired braking demand) transmitted to thedecentralized brake control module is processed as a desired pressurevalue by the pressure control circuit. The pressure control circuit isformed by a pressure controller implemented by software (electroniccontrol system), a pressure sensor and the pertaining analog input(input amplifier and AD-converter) of the electronic control system fordetecting the controlled variable, line terminals of the electroniccontrol system, electro-pneumatic pressure control valves as actuatorsand the relay valve for the pneumatic intensification of the flow rate.

In this case, the repeatability in the brake cylinder pressure controlin a distributed brake control system is more important in practice thanthe absolute precision of the set pressure value because a vehicleengineer always expects a constant braking performance and pays lessattention to the exact brake pressure. The effects of external actuatingvariables, such as the temperature, the drift, the aging, a fluctuatingsupply etc., on the components must therefore be taken into account.

The brake control module according to the invention is designed forcontrolling the service brake and emergency brake of a bogie. Itcontains the continuous brake pressure control in the defined pressurerange, the setting of an emergency braking pressure and an antiskidfunction. For the bogie module, a defined failure behavior is required;that is, a clearly defined condition of the brake occurs in everyoperating condition:

-   -   If the electronic system is operating perfectly, the brake is        released or can be adjusted by the braking demand;    -   if the electronic system is operating perfectly and an emergency        braking is triggered, the brake is activated with a load        correction and antiskid control;    -   if the electronic system is operating in a faulty manner and no        emergency braking is triggered, the brake is released;    -   if the electronic system is operating in a faulty manner, the        brake is activated with a fixed stage.

Furthermore, the brake system according to the invention carries out anantiskid control, in which case an antiskid control circuit permits themaintaining of an acceptable slip value also during poor coefficient ofadhesion conditions between the wheel and the rail. A skidding of thevehicle is effectively prevented by the antiskid control circuit. Forthis purpose, it consists essentially of rotational speed sensors at thewheel sets or at the transmission for detecting the actual wheel speed,of a processing logic implemented by software which is used forcomputing a reference speed as a measurement of the actual vehicle speedand for determining actuating commands for influencing the brakecylinder pressure in the event of the occurrence of excessive slipvalues at individual wheel sets, and of a suitable actuator forinfluencing the set brake cylinder pressure.

In the case of the decentralized brake control module, the brakecylinder pressure can also be influenced exclusively by way of thepressure control. Here, the antiskid control is applied to the pressurecontrol valves either parallel to the pressure controller or it uses thepressure control circuit as an actuator.

FIG. 6 schematically illustrates additional details of he brake system100 on a bogie 3. The electric lines are shown in FIG. 6 by means ofbroken lines. Pneumatic lines are indicated as solid lines. The devicesarranged in a bogie 3 are illustrated in a dash-dotted frame.

The electronic control system therefore has the central control unit 21which, from the vehicle data bus 23 and, in addition, from a predefiningdevice 26 acted upon by the operator of the railway vehicle, receivesthe data required for controlling the brake system. Thus, informationconcerning the type of the train formation, its length, mass, speed isavailable to the central control unit, as well as current operatingvalues, such as the slip, the axle load, the rotational wheel speed, theactual deceleration and the bogie load can be taken into account. Thesedata are emitted by the central control unit 21 and are fed by way ofthe braking data bus 24 to each local control unit 31. For illustratingthe method of operation, this local control unit 31 is divided in FIG. 6into individual control unit sections 31 a to 31 f for different devicesto be controlled. By means of the braking data bus 24, a train brakevalve 41 is also controlled.

The pneumatic system of the railway vehicle 1 has the compressed-airgenerating device 22 by which a main air reservoir line 42 is fed. Inaddition, by way of the train brake valve 41, a main air line 43 is fed.By way of corresponding devices, the individual vehicles of a trainformation can be connected to the main air line 43. In this case, apressure is defined at which the train brakes are completely released.This pressure can be set such by means of the central control unit 21that the railway vehicle is braked in the desired manner.

The main air reservoir line 42 is used for controlling the brakingdevices of a bogie 3 of the traction vehicle. For this purpose, acompressed air line 44 branches off the main air reservoir line 42 andguides compressed air by way of a shut-off valve 27 to a check valve 32arranged in the bogie 3 and to a compressed-air reservoir 33. Thiscompressed-air reservoir 33 is used for ensuring the usability of thebraking devices of each bogie 3 in the event of a failure of the mainair reservoir line 42.

Further, in this embodiment, the local control units 31 a to 31 e arecoupled to this compressed-air line 44. In this case, the local controlunits 31 a and 31 b have service brake valves, by means of which therequired brake cylinder pressure in brake devices 34 and 35 can beadjusted in a continuous manner.

Furthermore, the compressed air line 44 also supplies the local controlunit 31 c by means of which spring-loaded brakes in the braking devices34 and 35 can be activated.

The compressed-air line 44 also supplies a local control unit 31 d, bywhich cleaning blocks 36 can be controlled. In addition, a local controlunit 31 e is supplied which is used for controlling a flange lubricatingdevice 37.

In the present embodiment according to FIG. 6, another local controlunit 31 f is also indicated which does not necessarily have to bearranged in the bogie 3 and is used for activating a sanding device 38.However, these devices 38 can also be coupled directly to thecompressed-air reservoir line 42 instead of being coupled to thecompressed-air line 44.

In the present embodiment, the train brake valve 41 as well as the brakevalves in the local control units 31 a and 31 b operate according to thequiescent-current principle. In the event of a disturbance of thesystem, the train brake valve 41 therefore bleeds the main air line,while the brake valves ventilate the braking devices 34 and 35. As aresult, an emergency braking is triggered.

In FIG. 6, the invention is explained on the example of a bogie 3.According to its type and construction, the railway vehicle 1 can have adifferent number of bogies 3. As a rule, the leading vehicle has two or,as illustrated in FIG. 1, three bogies 3. As explained above, thesebogies 3 are constructed as decentralized modular systems which arecoupled by the vehicle body 2 also by way of the braking data bus 24 andthe compressed-air line 44.

In order to be able to minimize the size in the bogie 3, thecompressed-air reservoir 33 can be constructed integrally at the frameof the bogies 3 by seal-welding a partial area thereof. As analternative, the compressed-air reservoir 33 can also be installed in apartial area of the bogie frame. Furthermore, according to theinvention, the check valve 32 can also be arranged on the bogie frame.

The check valve 32 and/or the compressed-air reservoir 33 can beprovided once per bogie 3 or individually for every axle. Furthermore,only the check valve 32 or the compressed-air reservoir 33 can bearranged in the bogie.

In addition, the local brake control units can also utilize signals ofdevices for the monitoring and automatic operational management, such asATO (Automatic Train Operation), ATC (Automatic Train Control) or ATP(Automatic Train Protection), for controlling the braking operation.

Additional details of the brake system according to the invention arethe object of German Patent Applications with the Reference Numbers DE198 48 990.0, DE 198 48 992.7, DE 198 48 994.3 and DE 198 48 995.1 onwhich the priority is based and to whose complete disclosure contentreference is made here.

The invention therefore provides a brake system for a railway vehicle inwhich local electronic brake control units contribute to a significantsimplification of the supply logistics. As a result, not only theconstructive expenditures on the railway vehicle can be significantlyreduced but, in all operating conditions, the required braking functionsare also provided in order to be able to cause a reliable stoppage ofthe railway vehicle.

Although the present invention has been described and illustrated indetail, it is to be clearly understood that the same is by way ofillustration and example only, and is not to be taken by way oflimitation. The spirit and scope of the present invention are to belimited only by the terms of the appended claims.

1. A brake system for a railway vehicle having at least two bogiescomprising: a main air reservoir line fed by a compressed-air generatingdevice; a compressed-air line connecting the main air reservoir line topneumatic brake units and auxiliary pneumatic units independent of thepneumatic brake units on each bogie; a central control unit controllingthe pneumatic brake units and the auxiliary units by local electricbrake control units, which are mutually connected by a common brakingdata bus; and the local electronic brake control units being in thebogie or on a car body in the area of the bogie.
 2. The brake systemaccording to claim 1, including a main air line fed by thecompressed-air generating device under the control of a train brakevalve; and the central control unit controls the train brake valve by alocal electronic brake control unit, which is connected to the commonbraking data bus.
 3. The brake system according to claim 1, whereinsignals of a predefining device which can be operated by a trainengineer, signals of local devices for the detection of currentoperating values including one or more of slip, axle load, rotationalwheel speed, actual deceleration and bogie load, and signals of devicesfor the monitoring and automatic operational management (ATO, ATC, ATP)are available to the local electronic brake control unit on the inputside.
 4. The brake system according to claim 1, wherein brake signals ona central railway vehicle data bus are received by the central controlunit and corresponding brake signals are transmitted by braking data busto the local electronic brake control units.
 5. The brake systemaccording to claim 4, wherein brake signals are transmitted directlyfrom the central railway vehicle data bus to the local electronic brakecontrol units.
 6. The brake system according to claim 1, including alocal device for detecting current operating values, including one ormore of slip, axle load, rotational wheel speed, actual deceleration andbogie load, is arranged with respect to a wheel and/or with respect toan axle and/or in the bogie; and the respective local electronic brakecontrol unit is connected to the local device and use data availablefrom the local device in controlling the brakes.
 7. The brake systemaccording to claim 6, wherein by means of the data available to thelocal brake control unit, a conversion of the brake signals takes placesuch that a wear of the brakes can be achieved which is as uniform aspossible.
 8. The brake system according to claim 1, wherein the localelectronic brake control units, a train control unit, a predefningdevice in an engineer's cabs, the bogies and a local operating valuedetection devices are linked with one another by a safety loop.
 9. Thebrake system according to claim 1, wherein the compressed-air lineconnects each bogie with the main air reservoir line via a shut-offvalve, a check valve and a compressed-air reservoir, and the check valveand the compressed-air reservoir are in the bogie.
 10. The brake systemaccording to claim 9, wherein the control unit for the brakes and thecontrol units for additional pneumatic devices are connected to theshut-off valve before the check valve.
 11. The brake system according toclaim 1, wherein a frame and/or other constructive elements of the bogieare constructed at least in sections as a compressed-air reservoir. 12.The brake system according to claim 1, wherein a frame and/or otherconstructive elements of the bogie are provided at least in sections forreceiving a compressed-air reservoir.